Hollow stem chill vent chaplet



April 1, 1969 v R. c. WALTER v HOLLOW STEM CHILL VENT CHAPLET Filed June 20, 1966 r if m/ V m6 United States Patent 3,435,886 HOLLOW STEM CHILL VENT CHAPLET Richard C. Walter, Williamsville, N.Y., assignor to General Motors Corporation, Detroit, Mich., a

corporation of Delaware Filed June 20, 1966, Ser. No. 558,883 Int. Cl. B22c 23/ 00, 21/14; B22d 33/04 US. Cl. 164-410 3 Claims ABSTRACT OF THE DISCLOSURE In the art of metal casting a chaplet providing efficient communication between a core vent passage and a mold wall vent passage consisting of a hollow stem portion which is received in the core vent passage and a partially spherical head portion which engages the periphery of the mold wall vent passage whereby communication is maintained between the mold vent passage and the core vent passage without the need for accurate alignment of core and mold vent passages.

This invention relates to metal casting molds and more particularly to a means for venting core gases produced from organic binder bonded sand foundry cores during casting.

A conventional metal casting method involves suitably positioning an organic binder bonded sand core in a mold cavity and in providing a vent passage or hole extending deeply into the core which is arranged to be in communication with a vent passage in the mold wall. In the casting process the hot molten metal surrounding the core causes the organic binder in the core to burn and develop gases which must be vented from the mold cavity to prevent defects in the casting. The core passage referred to which communicates with the mold vent passage provides an avenue for escape of such gases. For eificient operation the surfaces of the core surrounding the edge of the vent passage must snugly engage the mold wall surfaces surrounding the inner edges of the mold vent passage. It frequently happens, however, that the core geometry is not perfect or the core is not positioned in the mold cavity perfectly so that the core surfaces surrounding the vent passage opening do not snugly engage the mold wall surfaces surrounding the mold vent opening with the result that during casting molten metal flows in the vent passages, plugs them, and prevents proper venting of the gases. This difiiculty makes it necessary to maintain critical close tolerances in the core-mold wall contact area referred to above.

It is the object of this invention to provide eificient means connecting a core vent passage and a mold wall vent passage whereby efiicient venting of core gases is effected and entry of molten metal to the vent passages is prevented without the need for maintaining close tolerances in the process of manufacturing the molds and cores.

A more specific object of this invention is to provide a tubular metal chaplet insertable between the core vent passage and the mold vent passage having a surface configuration adapted to adjustably engage the edges of one of the vent passages to provide an efficient connection between the core and the mold vent passages and at the same time perform a chill function whereby molten metal striking the chaplet surfaces is immediately solidified to prevent entry of molten metal into the vent passages in the event that a perfect closure is not formed between the chaplet and the vent passages.

These and other objects are accomplished by providing a metal chaplet having a generally mushroom configuration which consists esentially of a stern portion and Patented Apr. 1, 1969 a head portion with a passage formed longitudinally and centrally thereof. The outer axial end of the head portion is provided preferably with a partially spherical configuration and the inner side of the head is provided with a flat surface perpendicular to the longitudinal axis of the stem portion.

In use the stem portion of the chaplet is inserted in either the core passage opening or the mold vent passage opening and the partially spherical portions of the head are caused to engage the edges of the other opening. It will be appreciated that the partially spherical character of the chaplet head and the fact that it is of substantially greater diameter than the diameter of the opening which it engages will permit minor misalignment between the core opening and the mold opening and yet provide a suitably sealed conduit between these passages. Moreover, molten metal coming into contact with the chaplet will be chilled causing a solidification of such molten metal to prevent entry of molten metal into the vent passages in the event that a perfect contact between the chaplet head and adjacent opening is not effected in assembling the mold and core.

Other objects and advantages will be apparent from the following detailed description of the invention reference being had to the accompanying drawing in which:

FIGURE 1 is a fragmentary cross-sectional View of a mold for casting a cylinder block including the chaplet of this invention in position.

FIGURE 2 is a perspective view in partial cross section of the chaplet of this invention.

Referring now to the drawings and particularly in FIG- URE 2, the chaplet of this invention has a generally mushroomed configuration including a stern portion 10 and a head portion 12. The chaplet includes a. passage 14 longitudinally through the stem 10 and head 12 centrally thereof. The outer axial side of the chaplet 16 is provided with a partially spherical configuration. Preferably the inner side 18 of the head is provided with a planar or fiat annular configuration which is perpendicular to the longitudinal outer surfaces of the stem 10.

FIGURE 1 shows a portion of a sand mold for easting cylinder blocks illustrating the use of the chaplet shown in FIGURE 2. It includes a cope 20 and a drag 22 formed, for example, of conventional foundry green sand and defining a V-eight engine block casting cavity 23 therebetween in which there is positioned the barrel cores 2 4 and the water jacket cores 26. The water jacket cores 26 are shown provided with a vent passage or opening 28 extending through substantially the length of the core. The drag includes a vent passage 30' which at its inner end is generally aligned with the core vent opening 28 and which vents to the atmosphere.

In the preferred embodiment of the invention the stern portion 10 of the chaplet is inserted into the core passage 28 so that the inner perpendicular side 18 of the chaplet snugly engages fiat parallel surfaces 32 of the core surrounding the passage opening 28. The partially spherical surfaces 16 of the chaplet abut the inner edges 34 of the passage 30. The diameter of the chaplet head 12 is considerably greater than that of the core passage opening 28 or the mold vent 30 so that an effective contact is maintained between the inner edge of the passage 30 and partially spherical surfaces 16 of the head 12 even though the facing openings of the passages 28 and 30 are not perfectly aligned.

As previously indicated the chaplet of this invention is particularly suitable for use in connection with green sand molds although obviously it is useful in connection with other mold materials. The organic binder bonded cores contemplated in this invention are the conventional dry sand or oil bonded cores or thermosetting resin bonded cores involving thermosetting resins such as phenolformaldehyde, urea-formaldehyde resins and the like. Preferably the chaplet is formed of a suitably ductile ferrous metal by suitable metal-forming operations. However, other metals may be used as will be apparent to those skilled in the art.

As is indicated in FIG. 2 the chaplet walls are relatively thick so that the chaplet will effectively serve a chill function. A typical chaplet may have a longitudinal length of about /2 inch with the stem length being /8 inch. The stem diameter is about inch, the stem wall thickness and axial head thickness is about inch, and the head diameter is about /2 inch.

The use of the chaplet of this invention makes it unnecessary to maintain close tolerances between the mold and core vents in assembling the mold since the partially spherical head 16 thereof will accommodate a considerable misalignment. Moreover, in the casting process the chaplet will provide a chill for any molten metal coming into contact therewith in the area of the joint between the chaplet head 12 and the vent opening 30 causing it to solidify and prevent entry of molten metal into the vent assages.

Although the invention has been described in terms of a specific embodiment other forms may be adopted which are within the scope of the invention except as defined by the following claims.

I claim:

1. A mold construction comprising complementary sections forming a mold cavity therebetween,

a core positioned within said cavity having a portion thereof including a vent passage opening in close proximity to a wall of said cavity,

said wall including a vent passage extending therethrough having its inner opening generally aligned With core vent passage opening, a metal chaplet comprising a head portion and a stem portion and including a passage extending longitudinally therethrough said stem and said head centrally thereof, the outer axial surface of said head having a partially generally spherical configuration of substantially greater diameter than said stem and said passages,

said stem being received in one of said openings and said partially spherical surfaces engaging the edges of the other of said openings whereby said chaplet provides a self-adjusting fluid flow connection between said core vent passage and said mold wall passage and a chill adapted to prevent the entry of molten metal into the vent passages during casting.

2. Claim 1, wherein said stem portion is received in said core passage opening.

3. Claim 2, wherein the axial inner surfaces of said chaplet are perpendicular to said stem portion and engage flat surfaces of said core which .surround said core passage opening.

References Cited UNITED STATES PATENTS 636,438 11/1899 Lovejoy l64-398 1,023,633 4/1912 Fasy l64398 1,539,881 6/1925 Spencer et al 164399 2,344,128 3/1944 Cherry et a1. 77 2,803,984 8/1957 Swenson 8577 3,188,701 6/1965 McIntyre 164-410 J. SPENCER OVERHOLSER, Primary Examiner.

EUGENE MAR, Assistant Examiner.

US. Cl. X.R. 

